This invention relates to a damper for a stator vane of a gas turbine engine. Specifically, this invention relates to a damper for reducing vibration between a vane assembly and a seal secured to the vane assembly.
Gas turbine engines include alternating stages of rotating blades and stationary vanes. Each vane stage comprises a plurality of stator segments. A segment could include a plurality of vanes extending between an outer platform and an inner platform. Stator segments are commonly formed by casting or by brazing.
To relieve any build-up of stress caused by temperature gradients in the vanes and platforms during engine operation, the inner platform typically includes relief slits between adjacent vanes. These relief slits also help isolate vanes from vibration modes of adjacent vanes. The stator segment also includes a damper to reduce vibration amplitudes, thereby helping prevent vane cracking, The damper is typically formed into a spring by passing sheet metal through punch-press dies or forming rolls.
Conventional damper designs, however, have numerous drawbacks. First, conventional damper shapes can have asymmetric shapes that can apply unequalized damping forces to the mating surfaces on the stator assembly. Unequalized damping forces reduces the effectiveness of the damper. Second, conventional damper shapes require multiple passes through the punch-press dies or forming rolls. Multiple passes through the forming machines increases manufacturing costs. Third, the shape of conventional dampers (i.e. almost tubular) requires more material than is necessary for damping purposes. This additional material increases the weight of the engine.